Proto Labs, Inc.
US ˙ NYSE ˙ US7437131094

SecurityPRLB / Proto Labs, Inc.
InstitutionCitigroup Inc
Latest Disclosed Ownership15,208 shares
Latest Disclosed Value $ 867,160
Citigroup Inc ownership in PRLB / Proto Labs, Inc.

On May 11, 2026 - Citigroup Inc filed a 13F-HR form disclosing ownership of 15,208 shares of Proto Labs, Inc. (US:PRLB) valued at $867,160 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 15,313 shares of Proto Labs, Inc.. This represents a change in shares of -0.69% during the quarter. The current value of the position is $1,135,581 USD.

Citigroup Inc has a history of taking positions in derivatives of the underlying security (PRLB) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD and put options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

PRLB / Proto Labs, Inc. Historical Put/Call Ratio
Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date
Effective
Date
Form Security Class ID Avg Price
Paid (Est)
Reported
Shares
ΔShares ΔShares
(%)
Reported
Value
(x1000)
ΔValue
(%)
Alloc
(%)
ΔAlloc ΔAlloc (%) Cost Basis
(x1000)
Unrealized
Gain/Loss
(x1000)
2026-05-11 2026-03-31 13F PROTO LABS COM 743713109 15,208 -105 -0.69 867 12.02 0.0002
2026-02-13 2025-12-31 13F PROTO LABS COM 743713109 15,313 -6,824 -30.83 775 -30.08 0.0003
2025-11-10 2025-09-30 13F PROTO LABS COM 743713109 22,137 -13,776 -38.36 1,108 -22.96 0.0005
2025-08-11 2025-06-30 13F PROTO LABS COM 743713109 35,913 -5,251 -12.76 1,438 -0.35 0.0007
2025-05-12 2025-03-31 13F PROTO LABS COM 743713109 41,164 2,625 6.81 1,442 -4.25 0.0007
2025-02-12 2024-12-31 13F PROTO LABS COM 743713109 38,539 1,658 4.50 1,506 39.06 0.0009
2024-11-12 2024-09-30 13F PROTO LABS COM 743713109 36,881 13,636 58.66 1,083 50.84 0.0006
2024-08-12 2024-06-30 13F PROTO LABS COM 743713109 23,245 371 1.62 718 -12.12 0.0005
2024-05-10 2024-03-31 13F PROTO LABS COM 743713109 22,874 1,707 8.06 818 -0.85 0.0005
2024-02-09 2023-12-31 13F PROTO LABS COM 743713109 21,167 3,070 16.96 825 72.75 0.0006
2023-12-06 2023-09-30 13F/A-1 PROTO LABS COM 743713109 18,097 -10,135 -35.90 478 -51.62 0.0004
2023-11-09 2023-09-30 13F PROTO LABS COM 743713109 18,097 -10,135 478 0.0001
2023-08-10 2023-06-30 13F PROTO LABS COM 743713109 28,232 10,999 63.83 987 72.68 0.0006
2023-05-11 2023-03-31 13F PROTO LABS COM 743713109 17,233 -6,988 -28.85 571 -7.61 0.0004
2023-02-09 2022-12-31 13F PROTO LABS COM 743713109 24,221 86 0.36 618 -29.69 0.0005
2022-11-10 2022-09-30 13F PROTO LABS COM 743713109 24,135 1,870 8.40 879 -17.46 0.0006
2022-08-10 2022-06-30 13F PROTO LABS COM 743713109 22,265 -15,156 -40.50 1,065 -46.18 0.0008
2022-05-12 2022-03-31 13F PROTO LABS COM 743713109 37,421 -3,631 -8.84 1,979 -6.12 0.0012
2022-02-10 2021-12-31 13F PROTO LABS COM 743713109 41,052 10,702 35.26 2,108 4.30 0.0011
2021-11-10 2021-09-30 13F PROTO LABS COM 743713109 30,350 -14,695 -32.62 2,021 -51.14 0.0012
2021-08-10 2021-06-30 13F PROTO LABS COM 743713109 45,045 19,393 75.60 4,136 32.44 0.0025
2021-05-13 2021-03-31 13F PROTO LABS COM 743713109 25,652 -5,984 -18.92 3,123 -35.65 0.0020
2021-02-11 2020-12-31 13F PROTO LABS COM 743713109 31,636 1,178 3.87 4,853 23.05 0.0029
2020-11-12 2020-09-30 13F PROTO LABS COM 743713109 30,458 -4,509 -12.90 3,944 0.31 0.0026
2020-08-12 2020-06-30 13F PROTO LABS COM 743713109 34,967 12,148 53.24 3,932 126.37 0.0031
2020-05-12 2020-03-31 13F PROTO LABS COM 743713109 22,819 -855 -3.61 1,737 -27.78 0.0016
2020-02-12 2019-12-31 13F PROTO LABS COM 743713109 23,674 1,169 5.19 2,405 4.66 0.0017
2019-11-08 2019-09-30 13F PROTO LABS COM 743713109 22,505 11,938 112.97 2,298 87.44 0.0018
2019-08-12 2019-06-30 13F PROTO LABS COM 743713109 10,567 -2,051 -16.25 1,226 -7.54 0.0010
2019-05-13 2019-03-31 13F PROTO LABS COM 743713109 12,618 1,630 14.83 1,326 6.94 0.0013
2019-02-12 2018-12-31 13F PROTO LABS COM 743713109 10,988 7,222 191.77 1,240 103.61 0.0013
2018-11-13 2018-09-30 13F PROTO LABS COM 743713109 3,766 -388 -9.34 609 23.53 0.0005
2018-08-10 2018-06-30 13F PROTO LABS COM 743713109 4,154 -1,170 -21.98 493 -21.25 0.0005
2018-05-11 2018-03-31 13F PROTO LABS COM 743713109 5,324 2,265 74.04 626 98.10 0.0005
2018-02-12 2017-12-31 13F PROTO LABS COM 743713109 3,059 -20 -0.65 316 27.94 0.0003
2017-11-13 2017-09-30 13F PROTO LABS COM 743713109 3,079 111 3.74 247 24.12 0.0002
2017-08-11 2017-06-30 13F PROTO LABS COM 743713109 2,968 -18,905 -86.43 199 -82.20 0.0002
2017-05-12 2017-03-31 13F PROTO LABS COM 743713109 21,873 -23,499 -51.79 1,118 -52.02 0.0010
2017-02-10 2016-12-31 13F PROTO LABS COM 743713109 45,372 23,005 102.85 2,330 73.88 0.0021
2016-11-10 2016-09-30 13F PROTO LABS COM 743713109 22,367 6,776 43.46 1,340 49.22 0.0013
2016-08-12 2016-06-30 13F PROTO LABS COM 743713109 15,591 -7,284 -31.84 898 -49.06 0.0009
2016-05-13 2016-03-31 13F PROTO LABS COM 743713109 22,875 10,976 92.24 1,763 132.89 0.0020
2016-02-12 2015-12-31 13F PROTO LABS COM 743713109 11,899 6,626 125.66 757 114.45 0.0008
2015-11-13 2015-09-30 13F PROTO LABS COM 743713109 5,273 -293 -5.26 353 -6.12 0.0003
2015-08-13 2015-06-30 13F PROTO LABS COM 743713109 5,566 -3,738 -40.18 376 -42.15 0.0003
2015-05-14 2015-03-31 13F PROTO LABS COM 743713109 9,304 -1,022 -9.90 650 -6.20 0.0006
2015-02-17 2014-12-31 13F PROTO LABS COM 743713109 10,326 3,194 44.78 693 40.57 0.0006
2014-11-14 2014-09-30 13F PROTO LABS COM 743713109 7,132 137 1.96 493 -13.81 0.0004
2014-08-14 2014-06-30 13F PROTO LABS COM 743713109 6,995 -2,760 -28.29 572 -13.46 0.0005
2014-05-15 2014-03-31 13F PROTO LABS COM 743713109 9,755 -1,400 -12.55 661 -16.75 0.0007
2014-02-14 2013-12-31 13F PROTO LABS COM 743713109 11,155 5,839 109.84 794 95.57 0.0007
2013-11-14 2013-09-30 13F PROTO LABS COM 743713109 5,316 3,125 142.63 406 183.92 0.0004
2013-08-14 2013-06-30 13F PROTO LABS COM 743713109 2,191 2,191 143 0.0001
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2021-05-13 2021-03-31 13F PROTO LABS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2021-02-11 2020-12-31 13F PROTO LABS COM Call 1,300 -18.75 199 -3.86 n/a n/a n/a
2020-11-12 2020-09-30 13F PROTO LABS COM Call 1,600 -20.00 207 -8.00 n/a n/a n/a
2020-08-12 2020-06-30 13F PROTO LABS COM Call 2,000 150.00 225 268.85 n/a n/a n/a
2020-05-12 2020-03-31 13F PROTO LABS COM Call 800 -50.00 61 -62.35 n/a n/a n/a
2020-02-12 2019-12-31 13F PROTO LABS COM Call 1,600 -23.81 162 -24.30 n/a n/a n/a
2019-11-08 2019-09-30 13F PROTO LABS COM Call 2,100 23.53 214 8.63 n/a n/a n/a
2019-08-12 2019-06-30 13F PROTO LABS COM Call 1,700 -43.33 197 -37.46 n/a n/a n/a
2019-05-13 2019-03-31 13F PROTO LABS COM Call 3,000 -23.08 315 -28.41 n/a n/a n/a
2019-02-12 2018-12-31 13F PROTO LABS COM Call 3,900 -50.00 440 -65.13 n/a n/a n/a
2018-11-13 2018-09-30 13F PROTO LABS COM Call 7,800 -3.70 1,262 31.05 n/a n/a n/a
2018-08-10 2018-06-30 13F PROTO LABS COM Call 8,100 376.47 963 381.50 n/a n/a n/a
2018-05-11 2018-03-31 13F PROTO LABS COM Call 1,700 -70.69 200 -66.50 n/a n/a n/a
2018-02-12 2017-12-31 13F PROTO LABS COM Call 5,800 0.00 597 28.11 n/a n/a n/a
2017-11-13 2017-09-30 13F PROTO LABS COM Call 5,800 -4.92 466 13.66 n/a n/a n/a
2017-08-11 2017-06-30 13F PROTO LABS COM Call 6,100 916.67 410 1,222.58 n/a n/a n/a
2017-05-12 2017-03-31 13F PROTO LABS COM Call 600 20.00 31 19.23 n/a n/a n/a
2017-02-10 2016-12-31 13F PROTO LABS COM Call 500 26 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2021-02-11 2020-12-31 13F PROTO LABS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2020-11-12 2020-09-30 13F PROTO LABS COM Put 400 -60.00 52 -53.57 n/a n/a n/a
2020-08-12 2020-06-30 13F PROTO LABS COM Put 1,000 -16.67 112 23.08 n/a n/a n/a
2020-05-12 2020-03-31 13F PROTO LABS COM Put 1,200 50.00 91 12.35 n/a n/a n/a
2020-02-12 2019-12-31 13F PROTO LABS COM Put 800 100.00 81 97.56 n/a n/a n/a
2019-11-08 2019-09-30 13F PROTO LABS COM Put 400 100.00 41 78.26 n/a n/a n/a
2019-08-12 2019-06-30 13F PROTO LABS COM Put 200 -97.33 23 -97.08 n/a n/a n/a
2019-05-13 2019-03-31 13F PROTO LABS COM Put 7,500 92.31 789 79.32 n/a n/a n/a
2019-02-12 2018-12-31 13F PROTO LABS COM Put 3,900 -39.06 440 -57.49 n/a n/a n/a
2018-11-13 2018-09-30 13F PROTO LABS COM Put 6,400 28.00 1,035 73.95 n/a n/a n/a
2018-08-10 2018-06-30 13F PROTO LABS COM Put 5,000 21.95 595 23.44 n/a n/a n/a
2018-05-11 2018-03-31 13F PROTO LABS COM Put 4,100 105.00 482 133.98 n/a n/a n/a
2018-02-12 2017-12-31 13F PROTO LABS COM Put 2,000 -66.67 206 -57.26 n/a n/a n/a
2017-11-13 2017-09-30 13F PROTO LABS COM Put 6,000 900.00 482 1,105.00 n/a n/a n/a
2017-08-11 2017-06-30 13F PROTO LABS COM Put 600 500.00 40 700.00 n/a n/a n/a
2017-05-12 2017-03-31 13F PROTO LABS COM Put 100 5 n/a n/a n/a
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.